forked from OSchip/llvm-project
149 lines
5.9 KiB
LLVM
149 lines
5.9 KiB
LLVM
; REQUIRES: x86-registered-target
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; Test devirtualization through the thin link and backend, ensuring that
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; it is only applied when the type test corresponding to a devirtualization
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; dominates an indirect call using the same vtable pointer. Indirect
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; call promotion and inlining may introduce a guarded indirect call
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; that can be promoted, which uses the same vtable address as the fallback
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; indirect call that cannot be devirtualized.
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; The code below illustrates the structure when we started with code like:
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;
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; class A {
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; public:
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; virtual int foo() { return 1; }
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; virtual int bar() { return 1; }
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; };
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; class B : public A {
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; public:
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; virtual int foo();
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; virtual int bar();
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; };
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;
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; int foo(A *a) {
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; return a->foo(); // ICP profile says most calls are to B::foo()
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; }
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;
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; int B::foo() {
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; return bar();
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; }
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;
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; After the compile step, which will perform ICP and a round of inlining, we
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; have something like:
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; int foo(A *a) {
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; if (&a->foo() == B::foo())
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; return ((B*)a)->bar(); // Inlined from promoted direct call to B::foo()
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; else
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; return a->foo();
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;
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; The inlined code seqence will have a type test against "_ZTS1B",
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; which will allow us to devirtualize indirect call ((B*)a)->bar() to B::bar();
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; Both that type test and the one for the fallback a->foo() indirect call
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; will use the same vtable pointer. Without a dominance check, we could
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; incorrectly devirtualize a->foo() to B::foo();
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; RUN: opt -thinlto-bc -thinlto-split-lto-unit -o %t.o %s
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; Legacy PM
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; RUN: llvm-lto2 run %t.o -save-temps -pass-remarks=. \
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; RUN: -o %t3 \
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; RUN: -r=%t.o,_Z3bazP1A,px \
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; RUN: -r=%t.o,_ZN1A3fooEv, \
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; RUN: -r=%t.o,_ZN1A3barEv, \
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; RUN: -r=%t.o,_ZN1B3fooEv, \
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; RUN: -r=%t.o,_ZN1B3barEv, \
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; RUN: -r=%t.o,_ZTV1A, \
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; RUN: -r=%t.o,_ZTV1B, \
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; RUN: -r=%t.o,_ZN1A3fooEv, \
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; RUN: -r=%t.o,_ZN1A3barEv, \
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; RUN: -r=%t.o,_ZN1B3fooEv, \
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; RUN: -r=%t.o,_ZN1B3barEv, \
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; RUN: -r=%t.o,_ZTV1A,px \
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; RUN: -r=%t.o,_ZTV1B,px 2>&1 | FileCheck %s --check-prefix=REMARK
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; RUN: llvm-dis %t3.1.4.opt.bc -o - | FileCheck %s --check-prefix=CHECK-IR
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; New PM
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; RUN: llvm-lto2 run %t.o -save-temps -use-new-pm -pass-remarks=. \
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; RUN: -o %t3 \
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; RUN: -r=%t.o,_Z3bazP1A,px \
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; RUN: -r=%t.o,_ZN1A3fooEv, \
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; RUN: -r=%t.o,_ZN1A3barEv, \
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; RUN: -r=%t.o,_ZN1B3fooEv, \
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; RUN: -r=%t.o,_ZN1B3barEv, \
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; RUN: -r=%t.o,_ZTV1A, \
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; RUN: -r=%t.o,_ZTV1B, \
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; RUN: -r=%t.o,_ZN1A3fooEv, \
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; RUN: -r=%t.o,_ZN1A3barEv, \
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; RUN: -r=%t.o,_ZN1B3fooEv, \
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; RUN: -r=%t.o,_ZN1B3barEv, \
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; RUN: -r=%t.o,_ZTV1A,px \
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; RUN: -r=%t.o,_ZTV1B,px 2>&1 | FileCheck %s --check-prefix=REMARK
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; RUN: llvm-dis %t3.1.4.opt.bc -o - | FileCheck %s --check-prefix=CHECK-IR
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; We should only devirtualize the inlined call to bar().
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; REMARK-NOT: single-impl: devirtualized a call to _ZN1B3fooEv
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; REMARK: single-impl: devirtualized a call to _ZN1B3barEv
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; REMARK-NOT: single-impl: devirtualized a call to _ZN1B3fooEv
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target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
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target triple = "x86_64-grtev4-linux-gnu"
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%class.A = type { i32 (...)** }
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%class.B = type { %class.A }
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@_ZTV1A = linkonce_odr hidden unnamed_addr constant { [4 x i8*] } { [4 x i8*] [i8* null, i8* undef, i8* bitcast (i32 (%class.A*)* @_ZN1A3fooEv to i8*), i8* bitcast (i32 (%class.A*)* @_ZN1A3barEv to i8*)] }, align 8, !type !0
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@_ZTV1B = hidden unnamed_addr constant { [4 x i8*] } { [4 x i8*] [i8* null, i8* undef, i8* bitcast (i32 (%class.B*)* @_ZN1B3fooEv to i8*), i8* bitcast (i32 (%class.B*)* @_ZN1B3barEv to i8*)] }, align 8, !type !0, !type !1
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define hidden i32 @_Z3bazP1A(%class.A* %a) local_unnamed_addr {
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entry:
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%0 = bitcast %class.A* %a to i32 (%class.A*)***
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%vtable = load i32 (%class.A*)**, i32 (%class.A*)*** %0, align 8
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%1 = bitcast i32 (%class.A*)** %vtable to i8*
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%2 = tail call i1 @llvm.type.test(i8* %1, metadata !"_ZTS1A")
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tail call void @llvm.assume(i1 %2)
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%3 = load i32 (%class.A*)*, i32 (%class.A*)** %vtable, align 8
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; This is the compare instruction inserted by ICP
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%4 = icmp eq i32 (%class.A*)* %3, bitcast (i32 (%class.B*)* @_ZN1B3fooEv to i32 (%class.A*)*)
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br i1 %4, label %if.true.direct_targ, label %if.false.orig_indirect
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; This block contains the promoted and inlined call to B::foo();
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; CHECK-IR: if.true.direct_targ: ; preds = %entry
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if.true.direct_targ: ; preds = %entry
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%5 = bitcast %class.A* %a to %class.B*
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%6 = bitcast i32 (%class.A*)** %vtable to i8*
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%7 = tail call i1 @llvm.type.test(i8* %6, metadata !"_ZTS1B")
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tail call void @llvm.assume(i1 %7)
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%vfn.i1 = getelementptr inbounds i32 (%class.A*)*, i32 (%class.A*)** %vtable, i64 1
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%vfn.i = bitcast i32 (%class.A*)** %vfn.i1 to i32 (%class.B*)**
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%8 = load i32 (%class.B*)*, i32 (%class.B*)** %vfn.i, align 8
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; Call to bar() can be devirtualized to call to B::bar(), since it was
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; inlined from B::foo() after ICP introduced the guarded promotion.
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; CHECK-IR: %call.i = tail call i32 @_ZN1B3barEv(%class.B* %3)
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%call.i = tail call i32 %8(%class.B* %5)
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br label %if.end.icp
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; This block contains the fallback indirect call a->foo()
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; CHECK-IR: if.false.orig_indirect:
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if.false.orig_indirect: ; preds = %entry
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; Fallback indirect call to foo() cannot be devirtualized.
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; CHECK-IR: %call = tail call i32 %
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%call = tail call i32 %3(%class.A* nonnull %a)
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br label %if.end.icp
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if.end.icp: ; preds = %if.false.orig_indirect, %if.true.direct_targ
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%9 = phi i32 [ %call, %if.false.orig_indirect ], [ %call.i, %if.true.direct_targ ]
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ret i32 %9
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}
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declare i1 @llvm.type.test(i8*, metadata)
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declare void @llvm.assume(i1)
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declare dso_local i32 @_ZN1B3fooEv(%class.B* %this) unnamed_addr
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declare dso_local i32 @_ZN1B3barEv(%class.B*) unnamed_addr
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declare dso_local i32 @_ZN1A3barEv(%class.A* %this) unnamed_addr
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declare dso_local i32 @_ZN1A3fooEv(%class.A* %this) unnamed_addr
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!0 = !{i64 16, !"_ZTS1A"}
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!1 = !{i64 16, !"_ZTS1B"}
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